Epoxy resin powder coating compositions comprising an epoxy resin, a hardener, and a fillers are widely used for the insulation of electric and electronic parts. Also known are their applications for fixing rotor coils of motors and generators. That is, the entire coil is fixed to the rotor core with the resin to avoid the coil dropping out from the rotor core due to the intense centrifugal force generated from its rotation.
However, the conventional epoxy resin powder coating compositions to be used for the above purpose have poor adhesibility that had difficulty to firmly fix the coil to the rotor core.